The soil profile at a site consists of a 5 m thick sand and layer underlain by a $c-\varphi$ soil as shown in figure. The water table is found 1m below the ground level. The entire soil mass is retained by a concrete retaining wall and is in the active state. The back of the wall is smooth and vertical. The total active earth pressure (expressed in $kN/m^2$) at a point A as per Rankine's theory is .

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